I have 6 Zebra Danios and 7 Neon Tetras. One of my Danios is acting strange. He is lethargic, and lately has been hovering near the top of the tank. Earlier, he was flexing his back up sometimes and down sometimes. Fins seem to be extended, but last night they were clamped. He isn't with his friends. They swim around the tank very vigorously, but he's just hovering in the corner. I've included the form and pictures. Any help GREATLY appreciated! Thanks guys.

1. Size of tank? 29 gal

2. Water parameters
a. Ammonia? No test kit, should be zero or close to it
b. Nitrite? 0ppm
c. Nitrate? 0ppm
d. pH, KH and GH? 6.8ish, hardness is about 120ppm
e. Test kit? Mardel 5 in 1 Test Kit

3. Temperature? 76 degrees

4. FW (fresh water) or BW (brackish)? FW

5. How long the aquarium has been set up? about 3 weeks

6. What fish do you have? How many are in your tank? How big are they? How long have you had them? 6 Danios, 7 Neon Tetras. Mix of young and old for both breeds

7. Were the fish placed under quarantine period (minus the first batch from the point wherein the tank is ready to accommodate the inhabitants)? No

12. Foods? TetraMin Tropical Crisps, Omega One Freeze Dried Tubiflex worms
How often are they fed? 3 times a day

13. a. Any abnormal signs/symptoms? Fish is close to surface on one side of the tank. Fins not clamped. Tail bends down or up sometimes (see picture below). Above average respiration.
b. Appearance of poop? Haven't seen poop
c. Appearance of gills? Normal

14. a. Have you treated your fish ahead of diagnosis? No
b. What meds were used? None

An interesting case, my dear watson :hmm: ... almost everything seems fine. However, I think your feeding too much. three times a day? It depends on how much you feed, though. are you feeding with the tubifex worms every time? It might be getting them sick. Also, my danios get kinda slow when they've eaten too much. They also did this when the temperature was too low, but your seems just fine. If you reduce feeding and maybe increase the temp just a tad and in a few weeks if it doesn't improve, he might just be getting old or something, I don't know. Hope I helped! ;-)

PS: Happy Thanksgiving!!

PSS: lol in the second pic hes just sitting there, visible, and the other danio is like a whiz :-P